Re: (featurep 'multi-tty) => t on Windows

From:

Eli Zaretskii

Subject:

Re: (featurep 'multi-tty) => t on Windows

Date:

Fri, 12 Dec 2008 07:01:05 -0500

> Date: Fri, 12 Dec 2008 00:39:10 +0100
> From: "Juanma Barranquero" <address@hidden>
> Cc: address@hidden, address@hidden, address@hidden
>
> The point is, IMHO, that (featurep 'multi-tty) will allow the code to
> have some expectations, like the possibility of having simultaneous
> tty and GUI frames
Code that assumes such a possibility without testing for (featurep 'x)
(or something similar for Windows) is buggy and should be fixed. One
can build Emacs --without-x, in which case it cannot have both tty and
GUI frames. But such an Emacs is still multi-tty, since it can have
multiple tty frames.
> that currently the Windows port can not satisfy.
I think the situation on Windows is worse: there are some multi-tty
primitives that simply crash or cause Emacs to throw a signal. I
think you discovered that while testing the latest changes in
emacsclient. Or does my faulty memory fail me again?
> If the Windows port defines the multi-tty feature, it just dilutes its
> meaning. Is that not true for the DOS port?
The DOS port supports only one kind of frame, so several different
kinds are not an issue (again, assuming Lisp code without bugs
mentioned above).
When I worked on reviving the DOS port, I actively tried to break it
by using multi-tty primitives, but any use-case that can be reproduced
on DOS either worked or silently did nothing. That is why I didn't
bother to revoke the multi-tty feature in the DOS port. If someone
shows me a use-case that contradicts that, I will think again.